Musical instrument



Patented Apr. 3o, 1935 1,999,355

UNITED STATES PATENT oEElcE MUSICAL INSTRUMENTL Arthur N. Curtiss, Collingswood, N. J., assignor to Radio Corporation of 'American New York, N. Y., a corporation of Delaware Application December 16, 1933, Serial No. 702,653

1o claims. (ci. :i4-40s) v My inventionrelates to improvements in musition of a musical instrument constructed and cal instruments of the type wherein a vibratory set up in accordance with my invention; element in the form of a coiled spring or reedy Fig. 2 is an end elevational view, looking toward is struck and thereby caused to vibrate to prothe left in Fig. l; and 5 duce va musical note and, more particularly, to n Fig. 3 is a table of dimensions for a vibratory 5 the construction of the vibratory element per se. element constructed in accordance with my in- Development Work on musical instruments of vention, and capable of faithfully reproducing the character referred kto has been carried on the notes ofchimes or bells. With the object of obtaining an instrument, com- In Figs. 1 and 2, the vibratory element I0 is monly referred to as an electric carillon, which 4capable of reproducing a musical note having a l0 faithfully reproduces the sounds of chimes and/or definite pitch frequency, and may be considered bells. In this connection, it has been found that as being one of anumber of such elements mountthe capability of the instrument to exactlyV reed in bank formation and constructed and ady produce the sound of a chime or a bell depends justed to reproduce therespective notes in the upon a number of structural and physical charmusical scale.- One manner ofv supporting and l5 acteristics of the vibratory element. rThe varioperating the various elements is disclosed in ous constructions of vibratory elements proposed rthe copending application of Carroll D. Kentner, heretofore have been capable of reproducing the Serial No. 574,961, filedNovember 14, 1931, and sounds of chimes and bells with some degree of assigned to the Radio Corporation of America. l iidelity, but there has often been a very notice- As shown, the end of the straight portion of 20 yable distortion of some kind. `For example, the the element I0 is clamped between suitable blocks vibratory elements proposed'heretofore have been I2 and I4 by screws I6 which pass loosely through too rich in undesirable harmonics to bey entirely the block I4 and thread into the kblock `I2. Satisfactory for exactly reproducing the Sounds For the purpose of transforming the physical of bells and chimes andy furthermoreithese e1@- vibrotions of the element In into oiootrioai pui- 25 :eshave lacked the characteristic harmonics sations,'the element is supported with its straight portionv extendingthrough an'air gap in a mag- In Patent No. 1,907,936 issued to me M ay 9, 1933, i an improved construction of a vibratory element neme crcmt vhlhuxirtlalb progdd y afm;

rofthe character referred to is disclosed. While manen mggne o S a e o rm no s OW? 30 this constructionmakes possible satisfactory repik'up 601118 1S so disposed m the magnetic en production of a musical note of a. chime or bell, cult that as the @ement 'n Vibfate'e 1n the all' there is some poroeptibie distortion of the reprogap, aV Current is mduoed in thls coll at a freduction, quency corresponding to the frequency of vibrayWith the foregoing in mind, it is one of the tion. This current is then amplified and sup- 35 objects of my invention to provide an improved plied to a loud speaker or other acoustic device 'l construction of vibratory element of the charac- (not shown). f n l terfreferred to which is capable of a more faith- A striker, which may be in the form of a hamful reproducing action than has been possible mer 20, is suitably supported for manual or 40 with the various 4constructions proposed heretoelectrical operation to strike the element I 0 to 40 fore, and which has advantages over the prior set it into vibration. i constructions inthe way of a substantial de- The advantages of my improved construction crease in theattenuation or rate of decay of the over those proposed heretofore is attributed to vibrations in the reeds, a substantial reduction the characteristic shape ofthe supported end of of the quantityof undesirable undertones (subthe element, as shown in Fig. 2. The essential harmonics), andra substantial increase in the characteristic, particularly over the construction n number and quantity of desirable upper hardisclosed in Patent No. 1,907,936, resides in the monies. f d taper of the supported end' of the element to a Other objects and advantages will hereinafter neck 22 which is very narrow as compared with appear. .the width W of that part of the element which For the purpose of illustrating my invention, is nottapered. More specifically, the relation of an embodiment thereof is shown in the drawing, the width of the neck 22, or that part of the elelwherein Y Y i kment I0 directly at the point of support, to the l Figure. 1 is a front elevational view of a por- Width W of the part which is not tapered, is less 55 than one-fourth. In the disclosed embodiment of my invention, this relation is one-tenth.

Immediately at the neck 22 or smaller end of the taper, the width of the element increases abruptly to W or at least to several times the width of the neck to form the end portion 2f. by which the element is supported.

It has been found that by reason solely of the characteristic construction or shape of the supported end of the element that the latter has important advantages over the prior constructions in the way of a substantial decrease in the attenuation or rate of decay of the vibrations in the reed, a substantial reduction of the quantity of undesirable undertones (sub-harmonics), and a substantial increase in the number and quantity of desirable upper harmonics.

Any particular element for reproducing a musical note of a definite pitch frequency has characteristic relations between certain dimensions of this element and the pitch frequency. These relations, in my improved device, are different from those in the construction disclosed in Patent No. 1,967,936, on account of the characteristic taper of the supported end of the element.

One of these dimensions I refer to as the total vibrating length L of the element, and measure this along the element, from the neck 22, at the edge of the clamping blocks l2 and I4, to the free vibrating end 2S of the element. In my improved construction, L=A;ca, wherein :r is the pitch frequency, L is the total vibrating length of the element in inches, A is a factor within the range of 290 to 300, and a is an exponent of :c within the range of .44 to .45. Very satisfactory results have been obtained by making A substantially equal to 294.3 and by making the exponent a substantially equal to .4456.

Another important dimension in my improved construction is the hanging length HL, which is measured, as shown in Fig. l, from the neck 22, at the edge of the clamping blocks I2 and I4, to a line tangent to the spiral portion 28 of the vibratory element and perpendicular to the straight portion of the latter. In my improved construction, HL=Bxb, wherein HL is the hanging length of the vibratory element in inches, B is a factor within the range of 100 to 110, and b is an exponent of x within the range of .44 to .45. `i/'ery satisfactory results have been obtained by making B substantially equal to 104.9, and by making b substantially equal to .4456.

Another important dimension in my improved construction is the outside diameter D of the spiral portion 28, the relation being DzCc, wherein D is the outside diameter in inches, C is a factor witlL'n the range of 63 to 73, and c is an exponent of a: within the range of .44 to .45. Satisfactory results have been obtained by making C substantially equal to 67.46, and by making c substantially equal to .4456.

Another structural characteristic of my improved vibratory element resides in the number of degrees through which the spiral portion 28 extends. In the particular embodiment of my invention disclosed, the spiral portion 23 extends through substantially 330 degrees. In vibratory elements constructed in accordance with my invention, the number of degrees through which the spiral extends may be within the range of from 270 to d50 degrees, as might be desired. I have found that if the spiral extends beyond this range, the tone reproduced is too rich harmonics and that if the spiral does not come within this range the vibratory element lacks the characteristic harmonics of a bell of the corresponding note.

The tapered end of the element I I refer to as the slope (S), the relation being SzExe, wherein E is a factor within the range of 80 to 90, and e is an exponent of x Within the range of .44 to .45. Satisfactory results have been obtained by making E substantially equal to 84.4 and by making e substantially equal to .4456.

I propose to make the elements l0 from a very high grade tempered steel, the steel being tempered to between 1400 and 1530 degrees Fahrenheit, the material being gauge. Any other magnetically permeable material, or combination of materials having the required characteristics, may be used to make the elements l0. The width W of the material preferably is from 1/8" to 1/2". The width of the element does not affect the tone color, and is selected only to provide the desired stiffness.

For the purpose of preventing rusting of the elements, I propose 'to give the same a very light coat of cadmium. This is done without raising the temperature or subjecting the device to other conditions which might change the tonal qualities of the instrument.

The various dimensions given in Fig. 3 have been found to be satisfactory for a set of vibratory elements covering the various notes in the musical scale from the C one octave above middle C to high C.

I claim as my invention:

i. A vibratory element of the coiled-spring type for producing a musical note having a definite pitch frequency, said element having its supported end tapered toward the point of support, and being characterized by the existence of the following relations between the structural dimensions of said element and the pitch frequency: L=A:ra; HL=Brb; D=C.rc; and S=E;r; wherein .r is the pitch frequency, L is the total vibrating length in inches of said element, A is a factor within the range of 290 to 300, a is an exponent of :c within the range of .44 to .45, HL is the hanging length in inches of said element, B is a factor within the range of 100 to 110, b is an exponent of within the range of .44 to .45, D is the outside diameter in inches of the coiled portion of said element, C is a factor within the range of 63 to '73, c is an exponent of a: within the range of .44 to .45, S is the length in inches of said tapered end measured from the beginning to the end of the taper, E is a factor within the range of 80 to 90, and e is an exponent of within the range of .44 to .45.

2. A vibratory element as claimed by claim 1, further characterized by the fact that the coiled portion of said element is in the form of a spiral wherein the number of degrees through which the spiral extends is within the range of from 270 to 450 degrees.

3. A vibratory element of the coiled-spring type for producing a musical note having a definite pitch frequency, said element having its supported end tapered toward the point of support, and being characterized by the existence of substantially the following relations between the structural dimensions of said element and the pitch frequency: L=294.33:4455; HL=104.9:1:4456; D=G7.46:c--4456; and S=84.4:c--4456; wherein :c is the pitch frequency, L is the total vibrating length in inches of said element, HL is the hanging length in inches of said element, D is the outside diameter in inches of the coiled portion of element, and S is the length in inches of said n `tapered end.

4; A vibratory element as claimed in claim 3, further characterized by the fact that the coil portion of said element 'extends through substantially three hundred and thirty degrees.

5. A vibratory element of the coiled-spring type for producing a musical note having a defil nite pitch frequency, said element having its supported rend tapered toward the pointl of support, and characterized by the fact that at the narrow end of thev taper the width of said element increases abruptly to provide a 'relatively wide portion by which it can be supported for free vibratory movement from the point of support;

6. A vibratory element of the coiled-spring type for producing a musical note having a deflnite pitch frequency, said element having its supported end tapered toward the point of supportand characterized by the fact that the relation of the width of said element. directly at the point of support to the width of the untaperedv portion of ysaid element is less than onefourth. y

'7. vA vibratory element of the coiled-spring type for producing a musical note having a definite pitch frequency, said element having its supported end tapered toward the point of support and characterized by the factV that the relation of the Width of said element directly at the point of supportr to the width of the untapered portion of said element is of the order of yonetenth. f

8. A vibratory element of the coiled-spring type for producing a musical note having a. denite pitch frequency, said element having its supported end tapered toward the point of support and characterized by the fact that the length of said tapered end measured from the beginning to the end of the taper is within the range from 3 tok 6 inches and by the fact that the relation of the width of said element at the smaller end of the taper to the width at the larger end of the taper is of the order of onetenth.

9. A vibratory element of the coiled-spring type for producing a musical note having 'a definite pitch frequency, said element having its supported end tapered toward the point of support and characterized by the fact that immediately at the smaller end of the taper the width of said element is at least several vtimes the width of the smaller end of the taper to form an end kportion by which said element can be supported.

Y 10. A vibratory element of the kcoiled-spring `type for producing a musical note having a definite lpitch frequency, the supported end of said element being tapered to a neck whose width is relatively small as compared to the width of the untapered part of/said element, the width of the extreme end portion of said element beyond the neck being relatively large as compared to the Width of the neck, said extreme end portion constituting the means by which said element can be supported for free vibratory movement from the neck to its other end.

ARTHUR N. CURTISS.v 

